Quartz and potassium feldspar grains are the main constituents of granite.

Here's why:

* Quartz is a hard, durable mineral that gives granite its glassy appearance.

* Potassium feldspar (orthoclase or microcline) is a common mineral in granite, giving it its pink or white color.

Granite is a type of igneous rock, formed from the slow cooling and crystallization of magma deep underground.